Scientists move to slow spread of crop fungus

A farmer holds ears of wheat during the harvest on a farm 430km west of Brisbane, Australia, on Oct. 29 last year.

Photo: Reuters

Wheat experts are stepping up monitoring of a crop disease first found in Africa in 1999 to minimize the spread of the deadly fungus that is also a threat in Asia, experts said yesterday.

A “Rust-Tracker,” using data supplied by farmers and scientists, could now monitor the fungus in 27 developing nations across 42 million hectares of wheat — an area the size of Iraq or California.

“It’s the most serious wheat disease,” Ronnie Coffman, vice-chair of the Borlaug Global Rust Initiative (BGRI), said ahead of a meeting of wheat experts in Beijing from today until Thursday.

“If it gets started ... it’s like a biological firestorm,” he said.

Experts will review progress in combating the disease, with fungicides and 20 new resistant varieties developed in recent years.

The stem rust disease, forming reddish patches on plants like rust on metal, is known as Ug99 after it was found in Uganda in 1999. It has since spread as far as South Africa and north to Yemen and Iran.

The fungus, which can destroy entire wheat fields, is likely eventually to be carried worldwide on the winds. The biggest threat in coming years is a spread across Asia to Pakistan, India and China, the world’s top producer, Coffman said.

“Effective control often depends on finding out what is happening in distant regions, and the Rust-Tracker can help scientists assess the status of stem rust and other rust diseases,” said Dave Hodson, the developer of Rust-Tracker.

About 85 percent of wheat now in production worldwide was reckoned to be vulnerable to Ug99 and its variants, the BGRI estimated. Rich nations are far less vulnerable because they can afford to switch to new varieties or deploy fungicides.

Afghanistan, Bangladesh, Ethiopia, Egypt, India, Kenya, Nepal and Pakistan are on the front line of deploying rust-resistant varieties.

Coffman said that relatively minor amounts of wheat output had been lost so far.

“The only country under immediate threat of a dramatic loss of production is Ethiopia,” he said.

In Kenya, for instance, Ug99 had largely been brought under control because of shifts to new varieties. Another threat was from yellow rust, which has struck nations from Morocco to Uzbekistan in recent years.

The Ug99 fungus is among a series of threats to food supplies. A UN panel of scientists says heat waves, floods and droughts — like the one affecting the US — are likely to become more frequent because of manmade climate change.

Scientists were also studying ways to limit a woody plant known as barberry, where the fungus also lives and efforts to eradicate the plant seem to have reduced rust.

Coffman said that rust had been known at least since Roman times. About 40 percent of the US crop was destroyed in the early 1950s when rust swept up from Mexico.